In recent years, a projection-type liquid crystal display (LCD: Liquid Crystal Display) that projects an image onto a screen has been widely used not only at office but also at home. The projection-type liquid crystal display (a projector) generates image light by modulating light from a light source by using a light valve, and performs display by projecting the image light onto a screen. The light valve includes a liquid crystal panel, and light is modulated by, for example, active matrix driving of each pixel depending on a picture signal from outside. For this reason, improvement of image deficiency (such as flicker and display unevenness) of the liquid crystal panel is desired.
To suppress occurrence of the image deficiency of the liquid crystal panel, it is considerably important to prevent a TFT (Thin Film Transistor) element in a pixel circuit, specifically, a semiconductor layer included in the TFT element, from being irradiated with light. One reason for this is that irradiating the semiconductor layer (in particular, a LDD (Lightly Doped Drain) region) with light generates a light leakage current. For example, PTL 1 discloses a thin-film semiconductor device in which a semiconductor layer and a gate electrode are formed in this order above a scanning line, and the gate electrode and the scanning line are integrated by filling coupling apertures disposed on both sides of a channel region of the semiconductor layer, with the gate electrode, thereby enhancing a light-shielding state for the channel region. Further, PTL 2 discloses a projection-type display unit having a structure in which a semiconductor layer is disposed above a scanning line, and light-shielding films are disposed in a layer above a LDD region of the semiconductor layer with an insulating film interposed therebetween, thereby enhancing a light-shielding performance for the LDD region. Furthermore, PTL 3 discloses an electro-optical unit in which a semiconductor layer and a gate electrode section are formed in this order above a scanning line, and a first electroconductive film extending from the gate electrode section is embedded in contact holes with the scanning line, which are provided on both sides of a LDD region of the semiconductor layer, thereby enhancing a light-shielding property for the channel region. In addition, PTL 3 discloses a structure in which a second electroconductive film extending from a data line is formed above the first electroconductive film with an insulating film interposed therebetween, and this second electroconductive film is embedded in the contact holes with the scanning line, thereby further enhancing the light-shielding property for the channel region.